Abstract: A video transmission apparatus for a video teleconference terminal for displaying video signals with a proper aspect ratio in a video teleconference terminal which transmits and receives video signals representing pictures of different aspect ratios. The video transmitter determines, from among the video signals generated by the cameras having different aspect ratios, which signal should be transmitted to the receiving terminal by a key operation on the operation pad. The result of selection by the operation pad is sent via a video controller to a transmission video signal selector, which selects one of the outputs from the cameras according to the result. The video signal from the selected camera is output to a video signal transmitter as a transmission video signal. A CPU of the video controller recognizes the selecting operation on the operation pad and, accordingly, generates a display control signal which indicates an aspect ratio corresponding to the camera thus selected.

Abstract: The present invention is an induction motor control system which prevents an excessive induced voltage across the thyristors providing DC braking control. The amount of DC braking torque is controlled by the time of application of the DC braking voltage to the induction motor through a phase-control capacitor which sets the time of firing the braking thyristors within each half cycle of the AC voltage. In a first embodiment the firing of all the braking thyristors is inhibited upon application of the DC braking control signal until the half cycle of the AC voltage associated with a predetermined braking thyristor. In a second embodiment the firing of a predetermined braking thyristor is inhibited during the half cycle of the AC voltage of the application of the DC braking control signal and the next succeeding half cycle. In both embodiments the braking thyristors are fired during their associated half cycle of the AC voltage thereafter to apply a continuing DC braking voltage to the induction motor.